基于气固两相流的控尘理论及其在选煤厂应用研究
发布时间：2019-06-07 18:54
【摘要】：随着社会迅速发展,人们对粉尘污染的重视程度越来越高,粉尘治理的理论成为当今学者们研究的热点,其中粉尘颗粒逸散规律和不同控尘方法的降尘机理成为研究中的重点和难点。 为模拟不同粉尘逸散规律和控尘机理,通过气固两相流理论结合粉尘颗粒特性,构建了粉尘浓度扩散二流体三维数值计算模型以及颗粒轨道三维数值计算模型。并结合实践经验修正了计算模型方程,对不同曳力模型进行深入考察检验,选取了适用于粉尘颗粒运动的曳力模型,并考虑了颗粒和壁面间碰撞作用。 通过数值模拟和理论分析,结合在选煤厂皮带受料处的应用,分别研究了密封负压控尘机理和微雾控尘机理。对各粒级粉尘颗粒分别受气流变化和雾滴捕捉后的运移轨迹进行了数值模拟,得出了粉尘颗粒运动轨迹,并通过数值模拟和现场应用验证了两种控尘方法的高效性。 针对粉尘颗粒在皮带受料处的运移规律,创新性地提出了闭环回旋控尘方法,基于气固两相流理论和颗粒碰撞理论,对闭环回旋控尘机理进行了三维数值模拟及理论研究。研究表明,在普遍存在的管式落料系统中,由于落料的重力加速强制诱导,管下方气流能量大于上方气流能量,通过设置闭环实现了气流的回旋流动,回旋作用有效地耗散了气流的能量,进而达到降尘目的。现场应用验证了闭环回旋气流在大落差落料系统粉尘治理中的高效性,同时,该方法无需任何动力,是未来节能型除尘产品的发展方向。 结合在破碎站和落煤塔的应用,分别研究了“外阻内抑”(外围设抑尘网内部尘源点喷雾抑尘)和“内吸外抑”(塔内负压抽尘塔外喷雾抑尘)两种控尘机理。采用数值模拟、理论分析和现场实测相结合的手段,研究了风流影响下破碎站和落煤塔发尘机理、抑尘网对风流强度的抑制机理以及塔内高压气流的消除机理。通过数值模拟和现场应用,论证了“外阻内抑”和“内吸外抑”控尘方法对多粒级粉尘的控尘效果。 研究结果说明,经过对不同控尘方法的理论研究,应用其控尘机理,能够有效治理不同区域粉尘污染,并且结合两种或者两种以上的综合控尘,对大型污染源有良好的治理效果。本文应用气固两相流理论对控尘理论开展深入研究,旨在为丰富控尘理论和有效降低粉尘污染等发挥有效作用。
[Abstract]:With the rapid development of society, people pay more and more attention to dust pollution, and the theory of dust control has become the focus of scholars' research. Among them, the law of dust particle escape and the dust reduction mechanism of different dust control methods have become the key and difficult points in the research. In order to simulate different dust escape laws and dust control mechanisms, a three-dimensional numerical model of dust concentration diffusion and a three-dimensional numerical model of particle orbit are constructed by combining the theory of gas-solid two-phase flow with the characteristics of dust particles. Combined with practical experience, the calculation model equation is modified, and the different drag model is investigated and tested deeply. The drag force model suitable for dust particle movement is selected, and the collision between particles and wall is considered. Through numerical simulation and theoretical analysis, combined with the application of belt material in coal preparation plant, the mechanism of sealing negative pressure dust control and micro fog dust control are studied respectively. The movement trajectory of dust particles is simulated by numerical simulation after airflow change and droplet capture respectively, and the efficiency of the two dust control methods is verified by numerical simulation and field application. Aiming at the migration law of dust particles at belt material, a closed-loop cyclotron dust control method is proposed innovatively. based on the theory of gas-solid two-phase flow and particle collision theory, the mechanism of closed-loop cyclotron dust control is simulated and studied theoretically. The results show that in the common tubular blanking system, the air energy below the tube is larger than the upper air energy due to the forced induction of gravity acceleration of the blanking material, and the swirling flow of the air flow is realized by setting a closed loop. The circumflex effect effectively dissipates the energy of the air flow, thus achieving the goal of dust reduction. The field application verifies the high efficiency of closed loop swirl flow in dust control of large drop blanking system. At the same time, this method does not need any power and is the development direction of energy-saving dust removal products in the future. Combined with the application in crushing station and coal falling tower, two kinds of dust control mechanisms, "external resistance internal suppression" (external dust suppression net internal dust source point spray dust suppression) and "internal suction external suppression" (inner negative pressure dust extraction tower spray dust suppression) are studied respectively. By means of numerical simulation, theoretical analysis and field measurement, the dust generation mechanism of crushing station and coal falling tower under the influence of air flow, the suppression mechanism of dust suppression network on air flow intensity and the elimination mechanism of high pressure air flow in tower are studied. Through numerical simulation and field application, the dust control effects of "external resistance internal suppression" and "internal absorption and external suppression" on multi-particle dust are demonstrated. The results show that the dust pollution in different regions can be effectively controlled by using its dust control mechanism through the theoretical study of different dust control methods, and combined with two or more kinds of comprehensive dust control. It has a good control effect on large pollution sources. In this paper, the gas-solid two-phase flow theory is used to study the dust control theory in order to enrich the dust control theory and effectively reduce dust pollution.
【学位授予单位】：辽宁工程技术大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TD714.4
本文编号：2495011
[Abstract]:With the rapid development of society, people pay more and more attention to dust pollution, and the theory of dust control has become the focus of scholars' research. Among them, the law of dust particle escape and the dust reduction mechanism of different dust control methods have become the key and difficult points in the research. In order to simulate different dust escape laws and dust control mechanisms, a three-dimensional numerical model of dust concentration diffusion and a three-dimensional numerical model of particle orbit are constructed by combining the theory of gas-solid two-phase flow with the characteristics of dust particles. Combined with practical experience, the calculation model equation is modified, and the different drag model is investigated and tested deeply. The drag force model suitable for dust particle movement is selected, and the collision between particles and wall is considered. Through numerical simulation and theoretical analysis, combined with the application of belt material in coal preparation plant, the mechanism of sealing negative pressure dust control and micro fog dust control are studied respectively. The movement trajectory of dust particles is simulated by numerical simulation after airflow change and droplet capture respectively, and the efficiency of the two dust control methods is verified by numerical simulation and field application. Aiming at the migration law of dust particles at belt material, a closed-loop cyclotron dust control method is proposed innovatively. based on the theory of gas-solid two-phase flow and particle collision theory, the mechanism of closed-loop cyclotron dust control is simulated and studied theoretically. The results show that in the common tubular blanking system, the air energy below the tube is larger than the upper air energy due to the forced induction of gravity acceleration of the blanking material, and the swirling flow of the air flow is realized by setting a closed loop. The circumflex effect effectively dissipates the energy of the air flow, thus achieving the goal of dust reduction. The field application verifies the high efficiency of closed loop swirl flow in dust control of large drop blanking system. At the same time, this method does not need any power and is the development direction of energy-saving dust removal products in the future. Combined with the application in crushing station and coal falling tower, two kinds of dust control mechanisms, "external resistance internal suppression" (external dust suppression net internal dust source point spray dust suppression) and "internal suction external suppression" (inner negative pressure dust extraction tower spray dust suppression) are studied respectively. By means of numerical simulation, theoretical analysis and field measurement, the dust generation mechanism of crushing station and coal falling tower under the influence of air flow, the suppression mechanism of dust suppression network on air flow intensity and the elimination mechanism of high pressure air flow in tower are studied. Through numerical simulation and field application, the dust control effects of "external resistance internal suppression" and "internal absorption and external suppression" on multi-particle dust are demonstrated. The results show that the dust pollution in different regions can be effectively controlled by using its dust control mechanism through the theoretical study of different dust control methods, and combined with two or more kinds of comprehensive dust control. It has a good control effect on large pollution sources. In this paper, the gas-solid two-phase flow theory is used to study the dust control theory in order to enrich the dust control theory and effectively reduce dust pollution.
【学位授予单位】：辽宁工程技术大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TD714.4
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